Apparatus for the control and operation of electric lifts and the like



Aug. 16,1927.

. J. B. M. KNUTSEN APPARATUS FOR THE CONTROLAND OPERATION OF ELECTRIC LIFTS AND THE LIKE Filed Nov 25 1925 y. lhu'enfor as over-running points and the like "and it Patented Aug. 16, 19 27.

1 UNITED STATES PAT .ENT OFFICE.

JOHN BERTRAM MORTON KNUTSEN, OF POTTS POINT, NEAR SYDNEY, NEW SOUTH WALES, AUSTRALIA.

APPARATU FOR THE CONTROL AND OPERATION 015 ELECTRIC LIFTS AND THE LIKE.

Application filed November-23, 1925, Serial No. 70,934, and in Australia May 18, 1925.

This invention relates to ele tric lifts and the like but more especially refers to the control and regulation of the operation of lift machinery relative to fioor landings or other desired points ofstopping or control such "Furthe refers to the control of the opening of doors or gates relative to the position of the lift car or load. The objectofthe invent-ion is to provide an efiicient and accurate means switches. locks and the like which operate and control the doors. the-automatic floor levelling and floor setting mechanism, and the overrun limit swit hes and other well known devices associatedwith lifts. v

A. further object is to provide ardevice for these purposes which shall operatesilently and without making actual mechanical contact thus obviating the objectionable clatter and excessive wear associated with present svstem of control.

'I A further object is to provide a means of operation which can be-easily rendered inop' erative at ordinary points or zonesof operation when it is so desired.

The invention consists essentially in providing a magnetically operated" switch or other device, in the magnetic circuit of which an excessive air gap is formed the device bep ing so arranged that this air gap will be closed or almost wholly closed when it is desired that the device should operate.

When the magnet. is energized with the gap open the pull is-relatively small causing the switch or other device to remain inoperative, but when the air gap is closed or partially closed the pull is greatly. increased thusenabling the switch or device to openate.

The magnetic device may be placed on the lift car or load and is made to move in conformity therewith. At desired points of control the air gap or rather the part of the iron core or magnetic circuit adjacent to the air gap is made to pass close to an iron bar of suitable form adjustably fixed in the well. The air gap is considerably reduced and the magnetic pull greatly increasedso'that the switch or lock orother mechanism is caused to operate.

It is obvious that. no mechanical wear will takeplace and that no noise other than the very slight knock of the closing switch or other mechanism will be heard.

for controlling the various- In the accompanying drawings are shown diagrammatically several applications of the invention but it is to he understood that the invention is not restricted to the forms or fo the purposes shown therein.

Figure 1 is a diagrammatic perspective view of apparatus for door locking or like purposes. V

Figure 2 is a. diagrammatic perspective view of apparatus for the control of auto- "matic floor levelling mechanism or. the like.

Figure 3 is a diagrammatic side elevation large air gap. The magnet is mounted on and adapted to move with the lift car (not shown). At suitable positions on the lift well are placed rigid parallel bars 6 of mild steel or other suitable and well known magnetic material arranged to register with the free ends of the core 7 and having their ends or polepieces so disposed as to become ad jacent to an armature 8 which is pivoted in any suitable manner. The armature 8 is provided with means such as the arm and pinconnected rod 10 for operating the lock or other mechanism. This mechanism is constructed and operated in well known manner in accordance with well. known practice and is so arranged as to keep the armature 8 normally away from the bars 6 either by gravity or hy'any suitable arrangement of springs or the like. 7 7

In Figures '2 and .3 is shown apparatus suitable for controlling the operation of antomatic floor levelling mechanism. A frame 11 of non-magnetic material is rigidly attached to the lift car 13 and holds three cores 14, 15, and-16 which project beyond the frame so as to pass close to one or the other of the-magnetic metal members 17 and 18 which are adjustably fixed in the lift well. The middle or main core 15 is provided with an electro-inagnetic winding 19 and from an extension of this core are pivoted a pair of armatures 12 and 12 carrying contacts tionary contacts,22 and '23., These pairs of contacts are insulated and mounted in any well known manner while the armatures 12 and 12 are normally retained in such a manner as to keep the contacts apart. When the winding 19 is energized magnetic circuits through the main core 15, auxiliary cores 14 and 16 and armatures are established but when the lift car is within the range of one or 18, one of the air gaps between 14 and 15 or 15 an 16 is very materially reduced so that one of the pairs of contacts 20-22 or 21'-23 is closed owing to the increase of pull on the armature 12 or 12' corresponding towhichever of the two members 17 and. 18

is exerting its, influence.

For example, assuming that the lift car is moving downwards and is approaching a floor 24 at which .it is desired to stop and the car controller is put at the oflf position for that purpose, the winding 19 is immediately energized and owin to the virtual closing of the air gap 147-15 y the member or the otheijf the stationary members 17 17 the armature 12 1S attracted to close the contacts 20 and 22 to energize the circuit 25 which operates the automatic floor levelling mechanism to bring the car slowl and accurately to a stop in re ister with the floor 24, the contacts 20-22 ein opened as soon as the bars 14 and 15 pass eyond the end of the member 17 to cut out the floor levelling mechanism and allow the machinery to stop. Should the car and its machinery have 'energy suflicient to cause it to pass beyond the floor 24 the member 18 will partially close the air gap 15-16 thus causing the contacts 21-23 to close and energize the circuit 26 to operate mechanism of well known type to return the ear to the floor 24. On the upward journey the operation of the device would be the same, the necessary reversals being made in the controlling circuits in accordance with adopted 7 practice.

In Figure 4: is shown an arrangemefit suitable for use on alternating current circuits. It is virtually a transformer in which the primary and secondar windings and their cores are only brought into their correct relative positions when. itis desired that the device should operate. The primar winding 27 is energized and as soon as t e rigid bars 28 forming part of the magnetic circuit come opposite the members 29 and 30 the magnetic circuit is practicall completed and the secondary winding is energized and if this winding is short circuited as at 32 the pull will cause the part 29 of the magnetic circuit to move and operate the bell crank 33 and rod 34 or other device to actuate the required mechanism.

When the two parts of the magnetic circuit become separated, the mechanism would automatically return to normal.

The primary may be carried on the car and-a number of secondaries placed in the lift well at points which it would be desired to cause mechanism to operate.

The various windings or the like of the abovedescribed devices may only be energized when it is desired that the switchor device shall operate at any particular point. Mechanical wear and consequent noise is thus further eliminated. The means for energizing the coils may be operated by the movement of the car control switch or in an; other well known manner. t will'be clearly seen that the principle described above may be utilized for the control of the o eration of any mechanism dependent on t e position of a lift car or the like relative to a fixed point.

I claim y 1. In apparatus of the character described the combination, a. movable support, an electro-magnet on said support including a pole piece and additional pole pieces arranged at the sides of the first pole iece, stationary magnetic members respective y arranged to be received between and in ma netically conductive relation to thefirst po 0 piece and one or the other of the second pole pieces, and armatures associated with the second pole pieces, substantially as and for the purposes set forth.

2. Apparatus as claimed in claim 1, wherein the stationary magnetic members are arranged in spaced pairs and at predetermined points throughout the path of movement of the movable support, substantially as and for the purposes set forth.

3. In apparatus for controllin the stopping of a lift at the top of floor andings in a well, the combination, an electro-magnet on the lift including a pole piece, additional pole pieces arranged at the sides of the first pole piece, and armatures associated with the second pole pieces and magnetic members arranged in spaced" pairs adjacent each of the floor landings in the well and positioned to be received between and in magnetically conductive relation to thefirst pole piece and one or the other of the second pole pieces, substantially as andfor the purposes name to this specification.

JOHI IERTRAI HORTON KNUTSEN. 

